Production of fibre composite component part based on aluminium and polyurethane

Abstract

A method of producing a fiber composite component part has the following steps: a) providing two or more metal sheets each comprising an aluminum material; b) providing at least one textile fabric; c) providing an anhydrous mixture having one or more than one hardener having a uretdione having an NCO functionality of not less than two, one or more than one binder having hydroxyl groups to an OH functionality of three to six, and one or more than one cobinder having oxirane groups; d) coating the textile fabric with the anhydrous mixture, to obtain a mixture-coated fabric; e) applying energy to the mixture-coated fabric for the purpose of performing a first crosslinking reaction to react hardener, binder and cobinder to form a thermoplastic polymer adhering to the textile fabric; f) hot pressing the metal sheets and the textile fabric together with the thermoplastic polymer adhering thereto into a sandwich such that the thermoplastic polymer joins the metal sheets together while enclosing the textile fabric; g) forming the sandwich into a shaped article; and h) heat treating the shaped article to obtain the fiber composite component part, wherein the thermoplastic polymer undergoes a second crosslinking reaction to convert into a thermoset polymer.

Description

BACKGROUND OF THE INVENTION[0001]Field of the Invention[0002]The invention relates to the production of a fibre composite component part based on aluminium and polyurethane.[0003]Discussion of the Background[0004]Fibre composite component part refers to a component part which is a component part of a machine, of a land-, air-, space- or water-craft, of an apparatus, of an installation or of an appliance and which is constructed of different, indissolubly interconnected materials subject to the proviso that at least one material takes the form of fibres and at least one material takes the form of a matrix surrounding said fibres. The shape of this fibre composite component part is substantially the shape that is determined by its intended use. As a result, the fibre composite component part is virtually ready to install / use and, apart from minor secondary finishing, requires no further significant changes in shape before installation / use.[0005]The present fibre composite component pa...

AI Technical Summary

Benefits of technology

The invention provides a method for making fiber composite parts from aluminum and polyurethane in a commercial way. The method uses a special polyurethane composition that can undergo two crosslinking reactions. The first reaction converts the polyurethane into a thermoplastic polymer, and the second reaction fully crosslinks it into a thermoset material. The final high strength of the component part only comes after it has assumed its ultimate shape. The invention integrates the choice of chemicals with the mechanical processing steps, which results in a synergistic effect.

Problems solved by technology

The materials science of manufacturing fibre composite component parts is accordingly much more tricky than the materials science of producing component parts from homogeneous materials.

Producing such a component part is a supreme technical challenge, since the specific expertise of organic and inorganic chemistry, of metal processing and regarding the in-service conditions expected for the component part must be combined.

This method of production is disadvantageous in that it always leads to a planar laminate, the utility of which is limited by its flatness.

This method is incidentally also disadvantageous because of the rapid reaction of the isocyanate / polyol components to form the polyurethane, making it necessary to produce this composite component part under time pressure.

However, the thickness of the steel is an immense 2 to 20 mm, so the steel here is in the form of heavy plate which, unlike fine sheet (thickness <3 mm), is not coilable.

A laminate of this type is therefore impossible to process with a conventional panel press of the type used in automotive construction for example.

This method is disadvantageous in that the fibres, in the form of short fibre, are already present in the polyurethane raw material, thus preventing intentional alignment of the fibres in the direction of the later transmission / distribution of forces / stresses.

One disadvantage here is the aqueous formulation of the reactive polyurethane mixture, so water vapour has to escape from the laminate during the processing operation.

Unless all the water is successfully removed, internal corrosion of the steel sheets is likely.

In addition, the reported polyurethane composition is highly reactive, so shaping has to take place within a tight processing window.

Overall it appears to be questionable whether the method described in DE102012106206A1 is capable of producing a steel-PU composite component part on an industrial scale and in a commercially viable manner.

However, these storage-stable prepregs are disadvantageous in that they are not unreservedly useful for lamination with aluminium materials.

More particularly, they fail to achieve a sufficient level of aluminium polymer bonding for safely forming a laminate obtained therefrom, as Example 0 will demonstrate herein below.

Consequently, no method has been described to date for obtaining fibre composite component parts from an aluminium material and a polyurethane on an industrial scale and in a commercially viable manner.

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